1. Field Of The Invention
The present invention relates to wrenches. More particularly, the present invention relates to a hand-held power socket wrench, wherein the drive mechanism tangentially engages a drive gear to impart rotation to the power drive, which is adapted to receive a plurality of metric and non-metric sized sockets. Still more particularly, the present invention relates to an improved wrench assembly for right angle torque transmission comprising the improvement of a single ball bearing located within the wrench to adjustably constrain the axial motion and force of the drive shaft when the wrench is operated in a drive direction. Further, oil light bronze fittings constrain the axial motion and force of the drive shaft when it is operated in a reverse direction.
2. General Background
In the use of hand-held wrenches, under normal circumstances, the wrench is operated by rotational movement of the handle portion in an arc, following the engagement of a bolt head or nut by the hub or jaws portion of the wrench. However, in certain circumstances, the wrench is inserted into a very confined area, so that the movement of the handle portion of the wrench in an arc, in order to loosen or tighten the nut or bolt, is impossible, due to the confined space available. Even in the field of what are called ratchet wrenches, which allow ratching movement of the wrench for loosening or tightening, an oscillating movement of the handle is required, and again, in confined spaces, it becomes an impossibility. Therefore, there have been developed a line of wrenches, which utilize a shaft extending through the handle of the wrench, which engages a hub, so that rotation of the internal shaft, imparts rotation to the hub. The hub is affixed with a socket-type feature, so that the bolt head or nut fits snugly in the socket, and thus may be rotated as the hub is rotated.
There are several patents in the art which address this feature, the most significant found in a prior art search noted as follows:
U.S. Pat. No. 1,415,731, issued to Terry also discloses a ratchet wrench, having an internal pawl feature, which ratchets similarly to conventional ratchet wrenches.
U.S. Pat. No. 1,698,618, issued to Bigelow, operates in part as a power wrench by rotation of the handle, but in order to undertake the final tightening, the handle must be manually moved in an arc, which is difficult in a confined space.
U.S. Pat. No. 2,764,048, issued to Thompson discloses a ratchet wrench utilizing a geared relationship between the handle and the hub portion of the wrench. However, the invention, as a ratchet wrench still requires the ratcheting movement of the wrench handle which is difficult in confined spaces.
U.S. Pat. No. 4,362,072, issued to Tillman relates to a wrench having an internal shaft in the handle, a disk on the head of the wrench, which is gearingly engaged to the shaft, so that rotation of the shaft imparts rotation to the disc. The disc has an aperture which engages the nut. However, in this particular arrangement, the disc must be replaced to accommodate different size nuts or bolts, which is a difficult task during operation.
U.S. Pat. No. 4,592,254, issued to Wallis operates as a ratchet wrench by movement of a portion of the handle inward toward the head, so as to impart rotational movement to the drive head.
U.S. Pat. No. 5,090,273, issued in 1992, teaches a ratchet wrench, which does not have a handle member to drive the drive head, but is generally a ratchet wrench of the typical design.
U.S. Pat. No. 4,517,861, issued to Stemberger, teaches a right angle torque wrench. However, and importantly, in the Stemberger wrench, the axial motion created by driving the drive shaft and worm gear is constrained only by traditional ball bearings located around the end of the drive shaft (as shown in, e.g., FIGS. 3 and 12 of Stemberger). Compared to the improvement of the instant invention, the in-line, single ball bearing, the Stemberger wrench is clearly inferior to the wrench of the instant invention, as it does not adequately constrain axial motion and force as does the instant invention.
U.S. Pat. No. 5,345,845, issued to Myers, also teaches a right angle torque wrench. However, and importantly, like the Stemberger wrench, in the Myers wrench, the axial motion created by driving the drive shaft and worm gear is constrained only by traditional ball bearings located around the drive shaft (as shown in, e.g., FIG. 5 of the Myers patent). Like the Stemberger wrench, when compared to the improvement of the instant invention, the in-line, single ball bearing, the Myers wrench is clearly inferior to the wrench of the instant invention, as it does not adequately constrain axial motion and force as does the instant invention.
Importantly, all of the prior art wrenches fail to teach the critical improvement of the instant invention, the placement of a single, adjustable, in-line ball bearing at the end of the drive shaft, within the wrench, which provides adjustable control over the axial forces generated when the drive shaft is rotated in the forward, or drive, direction, when constraint upon the produced axial force is particularly necessary.